Yes you do.
If you are a GA resident, you do not have to pay sales tax as long is it is a private seller, even if out of state private seller.
Collected by the State when you register the vehicle.
the Washington State University is under government and University of Washington is private.
No
No you do not. Sales tax is what businesses use to pay to the state. It's the "state's share" on a taxable item. A private party seller is not a business, so legally they cannot charge a sales tax. For example they cannot sell a car for $2,000 plus tax. However, you WILL have to pay a use tax when you go to the DMV to register your vehicle. The use tax is basically the same exact rate as sales tax. The state will tax you anyway they can.
Yes.
EWU is a public Washington State educational institution.
yes. eighteen.
In short, you are screwed. there is no way to reclaim money from a private seller in any state. your best bet would be a CARFAX or AUTOCHECK BEFORE purchasing the vehicle. I know it sounds like a lot of trouble to go through, but better 15/20 dollars now than a car broken down in the driveway with a 3k estimate for repairs.
Unless the people living in Oregon are purchasing items in Washington state, no they would not pay Washington sales taxes.
The buyer usually fills out the bill of sale forms when purchasing products, but it depends on what state one is in. Laws in PA are different than laws in CA.
No. Minors are not able to enter into legal contracts.